Japanese Patent Application Laid-Open (JP-A) No. 2003-252134 (Patent Document 1) describes a bumper reinforcement strengthening structure wherein a strengthening plate is fixed to bumper reinforcement. Using the strengthening plate to strengthen the bumper reinforcement in this way enables the bumper reinforcement to be strengthened without increasing the length of the vehicle in the front-rear direction.
However, the strengthening plate in Patent Document 1 is configured by an integrally formed member with a rectangular U-shaped cross-section profile. The positioning accuracy demanded in assembly of a strengthening plate with such a configuration is difficult to achieve. In particular, since the bumper reinforcement curves along the vehicle width direction, it is difficult to achieve front-rear positioning accuracy while matching the curved shape.